[The Republican Party's] intellectual evolution (or maybe more accurately, its devolution) has reached a point of no return, in which allegiance to false doctrines has become a crucial badge of identity…

Once upon a time it was possible to take climate change seriously while remaining a Republican in good standing. Today, listening to climate scientists gets you excommunicated…

And truly crazy positions are becoming the norm.† A decade ago, only the G.O.P.ís extremist fringe asserted that global warming was a hoax concocted by a vast global conspiracy of scientists (although even then that fringe included some powerful politicians). Today, such conspiracy theorizing is mainstream within the party, and rapidly becoming mandatory; witch hunts against scientists reporting evidence of warming have become standard operating procedure, and skepticism about climate science is turning into hostility toward science in general.